any electricians out there?

[herb fellows]

I have an older house, nearly 100 years old. I have a place in the basement where a bx cable crosses a piece of conduit, just basically was laying on top of it.
My wife heard a 'buzzing noise' the other day, I couldn't hear it. As I turned to walk away, I noticed a small spark where the wires crossed.
How does a spark occur between 2 'sealed' lines? I looked at them both, no corrosion or anything going on. There are 2 tiny 'burn' marks on the bx.
This could have been going on forever, or maybe it just started, I don't know. As she just noticed the buzzing noise, I'm tending to think it's new.
But these wires have been this way forever. Besides why is it happening at all, why would it happen now? Confused.

[crokett]

Is the conduit metal? And by BX you mean the armored cable? If so, the conduit is supposed to be grounded, as is the BX and some current could be leaking to ground somewhere on either the BX or the conduit, so you are getting current flowing to ground. This is something that definitely needs to be checked. I would isolate them with rubber or several wraps of electrical tape, then call an electrician if you aren't comfortable finding the problem yourself.

[reddog552]

Sparking conduit

This is Very Dangerous.Shut off all breakers fed by conduit & Bx.Call electrican.U probablt have an open or bad connection on a "grounded conductor" "Neutral", the sparking is the ckt. trying to find a return path, there is now power running through the grounded metal parts of your house.

[herb fellows]

Thanks for the info. I'm not stupid enough (although some would argue this point!) to try to deal with this myself, I just wanted to get some basic info so I don't look like an idiot or an easy mark for the electrician.
I don't have a regular guy, so I'm pretty much stuck with the yellow pages.The downside of having 'handy' friends is that they also have never called in an electrician!

Yes, armored cable and metal conduit. They were crossing about 5 feet out of the box.
I shut off the breaker immediately, and separated the bx from the conduit for good measure.

I did touch both the bx and the conduit (gingerly!) while the wires were live and separated, and there was no electric as far as I could tell, no sensation from either one.
I used a remote temperature sensor on all the bx and conduit coming from the box, everything was at about 65-70 degrees, except the suspect bx which was 95 degrees between the box and the sparking spot.
I'll look at sockets and outlets, but I draw the line at going into the box, just don't have enough knowledge to do so.

[cgallery]

This is Very Dangerous.Shut off all breakers fed by conduit & Bx.Call electrican.U probablt have an open or bad connection on a "grounded conductor" "Neutral", the sparking is the ckt. trying to find a return path, there is now power running through the grounded metal parts of your house.

I'm not normally an alarmist, but I agree w/ this. You have current travelling your conduit or shield.

[phi1l]

sounds like something isn't grounded correctly. get a professional to look at it, it is hard to tell exactly what's going on there.

[cabinetman]

You asked for "any electricians". Well I don't know if those that answered are electricians, and furthermore I ain't even an electrician. But I may have an answer for you. Years ago I had a problem with wiring inside conduit that was very old. My electrician that fixed the problem explained that when current runs through wiring the wiring has the propensity to vibrate. After years of vibration, the sheathing can just wear off when in contact with metal.

Now...that could be the answer.
.

[herb fellows]

Thanks all. I'll have the electrician in as soon as this )(*(^(()*)(&*I) snow stops!

[toolguy1000]

the same thing can cause wire nuts to loosen over time. the cause and solution will be interesting. for the OP's sake, i hope the snow stops soon so he can address this concern and clue us in on what happened.

[herb fellows]

Well the snow is 10-18" in NY, and I wish I lived where it was 10", wherever that is! We were supposed to go to the ACC craft show in Baltimore today, that ain't happening.
I've got about 240 linear feet at 3-4 foot wide to shovel, no snow blower or any other 'fancy equipment:-(. Wife has a strong back though......

[herb fellows]

I just realized that I never posted the outcome to this, so even though it's ancient, I thought I would put it in here for future reference for somebody else.

The city installed a new water meter in my basement about 2 weeks before this happened. It never occurred to me to check what he had done. Turns out he disconnected the ground wire to the cold water pipe! He didn't totally disconnect it, actually, just made it loose so he could slide it out of his way to do the install, so to all appearances, it was looking normal.
Long story short, and $200 later, electrician tightened the ground connection, no more leakage! Thanks, water meter installer! I should send the bill to them, don't you think?!

[gsmittle]

I just realized that I never posted the outcome to this, so even though it's ancient, I thought I would put it in here for future reference for somebody else.

The city installed a new water meter in my basement about 2 weeks before this happened. It never occurred to me to check what he had done. Turns out he disconnected the ground wire to the cold water pipe! He didn't totally disconnect it, actually, just made it loose so he could slide it out of his way to do the install, so to all appearances, it was looking normal.
Long story short, and $200 later, electrician tightened the ground connection, no more leakage! Thanks, water meter installer! I should send the bill to them, don't you think?!

Yep, send them the bill, along with an explanation of what the meter installer did. You probably won't get any monetary satisfaction, but maybe the installer will wise up.

I'm not an electrician, nor do I play one on TV, but it seems to me there might still be a problem, since you obviously had current going to ground. I dunno…

g.

[Slik Geek]

it seems to me there might still be a problem, since you obviously had current going to ground.

I would suggest investigating where that ground current is coming from. The protective earth ground connection "normally" shouldn't be carrying any significant current. What little current in "normal" conditions that is carried in the ground wire is referred to as "leakage current". A computer, for example, normally has EMI filters on the AC mains input that will cause a small amount of leakage current to flow in the ground wire - less than a milliamp, or maybe up to a couple milliamps of current.

The basic purpose of the ground wire is to provide back-up safety so that in the event of an insulation failure, the current will flow to ground and the overload protection will open, rather than thru the hapless person who touches the failed device.

What concerns me is that you reported a 30 degree (Fahrenheit, I presume) temperature rise in the second of BX where the ground current was apparently flowing. That suggests the ground current is significant, causing heating of the ground conductor, which means that somewhere you may have an insulation fault or a component failure.

[reddog552]

Dito

Ur problem was not solved, Ground to water main had nothing to do with your problem.U got a better ground sys. now. BUT U still have voltage on ground Im betting. U have loose conections or bad connections somewhere. I have wired all my life. Industral, Comm. & Res.